|Ordered:||20 January 1941|
|Laid down:||3 July 1943|
|Launched:||6 May 1944|
|Commissioned:||7 July 1944|
|Fate:||Surrendered 9 May 1945|
|Status:||Sank on 4 December 1945|
|Class and type:||Type VIIC submarine|
|Height:||9.60 m (31 ft 6 in)|
|Draught:||4.74 m (15 ft 7 in)|
|Complement:||4 officers, 40–56 enlisted|
|Part of:||Kriegsmarine: 11th U-boat Flotilla|
|Commanders:||Oblt.z.S. Ralf Jürs|
|Operations:||1 patrol: 4 – 26 March 1945|
German submarine U-778 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine in World War II. She only completed one combat patrol and sank no Allied ships. She was surrendered to the Allies at Bergen on 8 May 1945.
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-778 had a displacement of 769 tonnes (757 long tons) when at the surface and 871 tonnes (857 long tons) while submerged. She had a total length of 67.10 m (220 ft 2 in), a pressure hull length of 50.50 m (165 ft 8 in), a beam of 6.20 m (20 ft 4 in), a height of 9.60 m (31 ft 6 in), and a draught of 4.74 m (15 ft 7 in). The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2,800 to 3,200 metric horsepower (2,060 to 2,350 kW; 2,760 to 3,160 shp) for use while surfaced, two Garbe, Lahmeyer & Co. RP 137/c double-acting electric motors producing a total of 750 metric horsepower (550 kW; 740 shp) for use while submerged. She had two shafts and two 1.23 m (4 ft) propellers. The boat was capable of operating at depths of up to 230 metres (750 ft).
The submarine had a maximum surface speed of 17.7 knots (32.8 km/h; 20.4 mph) and a maximum submerged speed of 7.6 knots (14.1 km/h; 8.7 mph). When submerged, the boat could operate for 80 nautical miles (150 km; 92 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 8,500 nautical miles (15,700 km; 9,800 mi) at 10 knots (19 km/h; 12 mph). U-778 was fitted with five 53.3 cm (21 in) torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.8 cm (3.46 in) SK C/35 naval gun, (220 rounds), one 3.7 cm (1.5 in) Flak M42 and two twin 2 cm (0.79 in) C/30 anti-aircraft guns. The boat had a complement of between forty-four and sixty.
The boat arrived at Horten in Norway on 28 February 1945 under the command of Kptlt. Ralf Jürs. She left Horten on her only war patrol on 4 March, completing the 23-day patrol on the 26 March 1945 at Bergen in Norway. No ships were sunk during the patrol and the U-boat was still at Bergen when she was surrendered to the Allies some six weeks later on 9 May 1945.
On 4 December 1945, she was being towed offshore by the Royal Navy, to be scuttled as part of Operation Deadlight, but foundered and sank before reaching the scuttling ground, at a point , 16 nautical miles (30 km; 18 mi) North East of Malin Head in around 70 metres (230 ft) of water.
The wreck was rediscovered by marine archaeologist Innes McCartney in 2001. In 2007, Derry City Council announced plans to raise the boat to be the main exhibit of a new maritime museum. Many of the other Operation Deadlight U-boats were used for target practice and sunk by gunfire, torpedoes, rockets or bombs. U-778, by contrast, is remarkably intact and lies in relatively shallow water.
On 3 October 2007 an Irish diver died whilst filming the wreck as part of the salvage project. In November 2009, a spokesman from the council's heritage museum service announced the salvage project had been cancelled for cost reasons.
- Helgason, Guðmundur. "The Type VIIC boat U-778". German U-boats of WWII - uboat.net. Retrieved 21 November 2008.
- Gröner 1991, pp. 43-46.
- Helgason, Guðmundur. "U-boat Patrols Patrols by U-778". German U-boats of WWII - uboat.net. Retrieved 19 March 2016.
- "U778 image from expedition gallery".
- Bowcott, Owen (20 August 2007). "Raise the U-boat: council plans to put Nazi sub in maritime museum". The Guardian.
- "Team to recover U-boat diver body". BBC. 3 October 2007. Retrieved 21 November 2008.
- "Costs sink plan to raise U-boat". BBC. 12 November 2009. Retrieved 25 November 2009.
- Busch, Rainer; Röll, Hans-Joachim (1999). German U-boat commanders of World War II : a biographical dictionary. Translated by Brooks, Geoffrey. London, Annapolis, Md: Greenhill Books, Naval Institute Press. ISBN 1-55750-186-6.
- Busch, Rainer; Röll, Hans-Joachim (1999). Deutsche U-Boot-Verluste von September 1939 bis Mai 1945 [German U-boat losses from September 1939 to May 1945]. Der U-Boot-Krieg (in German). IV. Hamburg, Berlin, Bonn: Mittler. ISBN 3-8132-0514-2.
- Gröner, Erich; Jung, Dieter; Maass, Martin (1991). U-boats and Mine Warfare Vessels. German Warships 1815–1945. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4.
- Helgason, Guðmundur. "The Type VIIC boat U-778". German U-boats of WWII - uboat.net. Retrieved 29 December 2014.